|BT-2, BT-5, BT-7, BT-7M|
BT-5 Side view
|Type||Light cavalry tank|
|Place of origin||Soviet Union|
|Wars||Spanish Civil War|
Second Sino-Japanese War
Soviet-Japanese border conflicts
World War II
|Designer||J. Walter Christie, Kharkiv Morozov Machine Building Design Bureau (KMDB)|
|No. built||BT-2: 650 BT-5: 1884 BT-7: 5556|
|Variants||BT-2, BT-5, BT-7, BT-7M|
|Mass||11.5 tonnes (12.676 tons)|
|Length||5.58 m (18 ft 4 in)|
|Width||2.23 m (7 ft 4 in)|
|Height||2.25 m (7 ft 5 in)|
|45-mm Model 32 tank gun|
|7.62-mm DT machine gun|
400 hp (298 kW)
|Fuel capacity||360 litres (95 US gal)|
|200 km (120 mi)|
|Speed||72 km/h (44.7 mph)|
The BT tanks (Russian: ? (), romanized: Bystrokhodny tank, lit. "fast moving tank" or "high-speed tank") were a series of Soviet light tanks produced in large numbers between 1932 and 1941. They were lightly armoured, but reasonably well-armed for their time, and had the best mobility of all contemporary tanks. The BT tanks were known by the nickname Betka from the acronym, or its diminutive Betushka. The successor of the BT tanks would be the famous T-34 medium tank, introduced in 1940, which would replace all of the Soviet fast tanks, infantry tanks, and medium tanks in service.
The BT tanks were "convertible tanks". This was a feature designed by J. Walter Christie to reduce wear of the unreliable tank tracks of the 1930s. In about thirty minutes, the crew could remove the tracks and engage a chain drive to the rearmost road wheel on each side, allowing the tank to travel at very high speeds on roads. In wheeled mode, the tank was steered by pivoting the front road wheels. Soviet tank forces soon found the convertible option of little practical use; in a country with few paved roads, it consumed space and added needless complexity and weight. The feature was dropped from later Soviet designs.
Christie, a race car mechanic and driver from New Jersey, had failed to convince the U.S. Army Ordnance Bureau to adopt his Christie tank design. In 1930, Soviet agents at Amtorg, ostensibly a Soviet trade organization, used their New York political contacts to persuade U.S. military and civilian officials to provide plans and specifications of the Christie tank to the Soviet Union. At least two of Christie's M1931 tanks (without turrets) were later purchased in the United States and sent to the Soviet Union under false documentation, in which they were described as "agricultural tractors". Both tanks were delivered to the Kharkov Komintern Locomotive Plant (KhPZ). The original Christie tanks were designated fast tanks by the Soviets, abbreviated to BT (later referred to as BT-1). Based both on them and on other plans obtained earlier, three unarmed BT-2 prototypes were completed in October 1931 and mass production began in 1932. Most BT-2s were equipped with a 37 mm gun and a machine gun, but a shortage of 37 mm guns led to some early examples being fitted with three machine guns. The sloping front hull (glacis plate) armor design of the Christie M1931 prototype was retained in later Soviet tank hull designs, later adopted for side armor as well. The BT-5 and later models were equipped with a 45 mm gun.
Soviet Union variants:
|weight||10.2 t||11.5 t||14 t||14.5 t||14.7 t|
|length||5.58 m||5.58 m||5.66 m||5.66 m||5.66 m|
|width||2.23 m||2.23 m||2.29 m||2.29 m||2.29 m|
|height||2.20 m||2.25 m||2.42 m||2.52 m||2.42 m|
|armour||6-13 mm||6-13 mm||6-13 mm||6-13 mm||6-22 mm|
|main gun||37 mm
|45 mm |
|96 rounds||115 rounds||146 rounds||50 rounds||146 rounds|
|450 hp |
|620+170 l |
|road speed||100 km/h (62 mph)||72 km/h (45 mph)||86 km/h (53 mph)||86 km/h||86 km/h|
|power:weight||39 hp/t||35 hp/t||36 hp/t||34 hp/t||31 hp/t|
|road range||300 km||200 km||250 km||250 km||700 km|
|tactical range||100 km||90 km||120 km||120 km||400 km|
In the Spanish Civil War, a regiment of 50 BT-5s fought on the Republican side. They were manned by the members International Brigades trained in USSR and by some Soviet tankists. Their first combat on 13 October 1937 during the Zaragoza Offensive was disastrous: 13 tanks were lost due to bad tactics. Later, 12 were lost from December 1937 to February 1938 during battle of Teruel. A few captured BT-5s were also used by Nationalists.
During the Battles of Khalkhin Gol (also known as the Nomonhan Incident), which lasted from May to September in 1939, BT tanks were easily attacked by Japanese "close quarter" teams (tank killer squads) which were--in lieu of anti-tank weapons--armed with petrol bottles (later called "Molotov cocktails"). The Soviet BT-5 and BT-7 light tanks, which had been operating in temperatures greater than 100F on the Mongolian plains, easily caught fire when a Molotov cocktail ignited their gasoline engines. General Georgy Zhukov made it one of his "points" when briefing Joseph Stalin, that his "...BT tanks were a bit fireprone...." Conversely, many Japanese tank crews held the Soviet 45mm anti-tank/tank guns in high esteem, noting, "...no sooner did they see the flash from a Russian gun, than they'd notice a hole in their tank, adding that the Soviet gunners were accurate too!"
After the Khalkhin Gol War in 1939, the Soviet military had broken into two camps; one side was represented by Spanish Civil War veterans General Pavel Rychagov of the Soviet Air Force, Soviet armour expert General Dimitry Pavlov, and Stalin's favorite, Marshal Grigory Kulik, Chief of Artillery Administration. The other side consisted of the Khalkhin Gol veterans led by Generals Zhukov and Grigory Kravchenko of the Soviet Air Force. The lessons of Russia's "first real war on a massive scale using tanks, artillery, and airplanes" at Nomonhan (Khalkhin Gol) went unheeded. During the Finland War (Winter War), BT-2 and BT-5 tanks were less successful.
During the final weeks of World War II, a significant number of BT-7 tanks took part in the Soviet invasion of Manchuria against the Japanese occupation, in August 1945. This was the last combat action for the BT tanks.
During the Second World War in Europe, BT-5 and BT-7 tanks were used in the 1939 Soviet invasion of Poland and in large numbers in the battles of 1941, during which thousands were abandoned or destroyed. A few remained in use in 1942, but were rare after that time. The Red Army planned to replace the BT tank series with the T-34 and had just begun doing so when the German invasion (Operation Barbarossa) began.
The BT tank series was numerous, forming the cavalry tank arm of the Red Army in the 1930s and had much better mobility than other contemporary tank designs. For these reasons, there were many experiments and derivatives of the design, mostly conducted at the KhPZ factory in Kharkov.
The most important legacy of the BT tank was the T-34 medium tank. In 1937, a new design team was formed at the KhPZ to create the next generation of BT tanks. Initially, the chief designer was Mikhail Koshkin and after his death, Morozov. The team built two prototypes. The light one was called the A-20. The more heavily armed and armoured BT derivative, the A-32, was a "universal tank" to replace all the T-26 infantry tanks, BT cavalry tanks and T-28 medium tanks. Such a plan was controversial, but concerns about tank performance under the threat of the German blitzkrieg led to the approval for production of a still more heavily armoured version, the T-34 medium tank.
Along the way, an important technical development was the BT-IS and BT-SW-2 testbed vehicles, concentrating on sloped armour. This proof-of-concept led directly to the armour layout of the T-34. BT tank chassis were also used as the basis for engineering support vehicles and mobility testing vehicles. A bridgelayer variant had a T-38 turret and launched a bridge across small gaps. Standard tanks were fitted as fascine carriers. The RBT-5 hosted a pair of large artillery rocket launchers, one on each side of the turret. Several designs for extremely wide tracks, including, oddly, wooden 'snowshoes' were tried on BT tanks.
The KBT-7 was a thoroughly modern armoured command vehicle that was in the prototype stage when World War II broke out. The design was not pursued during the war.
In the Kiev manoeuvres of 1936, foreign military observers were shown hundreds of BT tanks roll by a reviewing stand. In the audience were British Army representatives, who returned home to advocate for use of Christie suspension on British cruiser tanks, which they incorporated from the Cruiser Mk III onwards. The pointed shape of the hull front armor on the BT tank also influenced the design of the British Matilda tank.